1. Field of the Invention
The present invention relates to a cross-country ski boot that includes a collar mounted pivotally on an upper provided with a sole, and relates to a device for adjusting the rearward movement of the collar, from a predetermined initial angular position, so as to selectively enable the boot to be adapted for the alternating step technique or the skating step technique.
2. Description of Background and Relevant Information
The known cross-country ski boots of the aforementioned type generally have a relatively low upper that fits the foot, on which a collar, that surrounds the lower part of the leg, is pivotally mounted via assembling means allowing its removal. Thus, for the skating step technique, the collar is kept in place so as to provide rear support for the lower part of the leg, as well as a good lateral holding of the ankle and, conversely, for the alternating step technique, the collar is removed in order to offer as much freedom of movement to the articulation of the ankle as possible, especially in the direction of the front-to-rear extension. These means for assembling the collar on the upper therefore constitute the equivalent of an adjusting device, since they make it possible to selectively adapt a single type of cross-country ski boot for two different techniques of cross-country skiing. By way of example, one can cite the German Utility Design No. 295 18 019 and the European Patent Publication No. 486 801 that describe such cross-country ski boots.
Other cross-country ski boots are also known, whose pivoting collar can be adjusted with respect to the low upper in order to offer more or less freedom of movement to the articulation of the ankle in the direction of the front-to-rear extension. The International Patent Publication No. WO 91/07889 describes such a boot and especially shows an adjusting device which, located in the area of the pivoting axis of the collar on the low upper, makes it possible to provide the collar with more or less movement in the front-to-rear direction.
To this end, a fixed abutment affixed to the collar cooperates, in the area of the articulation of the latter, with an abutment that can be adjusted in position on the low upper of the boot. As a result of this construction, it is the modifying of the position of the adjustable abutment on the low upper that determines the pivoting limit of the collar in the front-to-rear direction. Therefore, the articulation of the ankle can be provided with sufficient freedom of movement in the front-to-rear direction for the alternating step technique, despite the presence of the collar.
Moreover, still by means of the adjustable abutment, it is possible to limit the rearward tilting of the collar so as to provide rear support to the lower part of the leg, which is useful for bringing back the ski when propulsion ceases during the skating step technique. The adjusting device used in the area of the articulation of the collar therefore makes it possible, as in the preceding examples, to adapt a single type of cross-country ski boot for two different techniques of cross-country skiing, without dismounting the collar.
Conversely, it has the disadvantage of requiring the use of materials with high mechanical properties to obtain the various constituent parts of the adjusting device, as well as those of the collar and of the upper. Indeed, since the collar functions according to the principle of a lever, the forces applied thereto are multiplied considerably in the area of the abutments, because the latter are very close to its pivoting axis. Therefore, they, as well as the parts that carry them, must be very resistant, which results in a boot whose general structure is relatively rigid. Moreover, the boot is uncomfortable because the cooperation of the abutments with one another always translates into a firm support that is reflected as an impact on the rear portion of the lower part of the leg, especially during the extension of the foot.
Known cross-country ski boots that are more specifically designed for the skating step technique, such as that described in the Swiss Patent No. 675 951, can still be used for the alternating step technique. According to this document, the cross-country ski boot has a collar that is pivotally mounted by journals on an upper provided with a sole and a collar retaining device active from a predetermined angular position of the collar with respect to the upper, and only in the front-to-rear direction. To this end, the device is positioned in the rear portion of the boot and comprises, on the upper, a fixed abutment that is functional only in the top-down direction with the lower rear edge of the collar. In this way, the collar is stopped in rearward pivoting by the fixed abutment of the upper and remains free of pivoting forwardly. This construction therefore enables the bending movement of the ankle during the xe2x80x9cregroupingxe2x80x9d phase in executing the alternating step. Conversely, for such use, the freedom of movement of the ankle in the front-to-rear direction is very limited because of the blocking of the collar in rearward pivoting. As a result of this limitation, the user is forced to perform low amplitude steps, otherwise, the rear portion of the lower part of his leg is subject to painful pressures in the contact zone with the upper edge of the collar.
In fact, it is noted that even by making careful movements, repeating alternating steps nevertheless causes irritation, heating, pain, etc., which is why these boots are seldom used for the alternating step.
A partial solution to this dual purpose use of a cross-country ski boot, which does not comprise an adjusting device to optimize its adaptation to the alternating step or to the skating step, is presented with the boot that is taught in the European Patent Publication 596 281. Indeed, in this boot, the blocking of the collar in rearward pivoting is progressive due to the use of an elastic shock absorbing element between the collar and the upper which serves as a support means, and this element can be provided to be more or less flexible. The support on the upper edge of the collar is therefore more flexible, more absorbed than in the cross-country ski boots described in Swiss Patent 675 951, which avoids the impacts with the rear portion of the lower part of the leg. The fact remains true that over time, repeating the alternating steps generates irritation, heating, etc., due to the fact that the collar cannot tilt freely toward the rear, i.e., without encountering the elastic resistance of the support means. Finally, it is noted that the use of these boots having rear support absorption, as for the preceding boots, remains truly occasional in the alternating step technique because they cause the same discomforts over time.
An object of the invention is to propose a cross-country ski boot having a pivoting collar that can be easily adapted to assume the specific characteristics of the alternating step and skating step techniques, especially without it being necessary to dismount the collar and without intervening in the area of the pivoting axis thereof.
In particular, the invention aims at using an adjustable device for retaining the collar that is capable of maintaining the latter in the front-to-rear direction, in a predetermined angular position with respect to the upper adapted for the skating step technique, on the one hand, and of releasing the collar in rearward pivoting to enable the alternating step technique, on the other hand, whether or not the collar comprises an elastic shock absorbing element interacting between it and the upper.
More specifically, the device is provided to be capable of releasing the collar in rearward pivoting, over a pivoting amplitude that is at least sufficient to enable the extension of the ankle and of the foot of the back leg when thrust ceases in the alternating step technique. Conversely, the retaining device is also provided to be capable of blocking the collar in rearward pivoting, so as to provide the lower part of the leg with rear support, which is useful for bringing back the ski when the propulsion ceases in the skating step technique.
To achieve this object, the cross-country ski boot has a collar that is pivotally mounted by journals on an upper, and a device for retaining the collar that is active from a predetermined angular position and only in the front-to-rear direction by means of a fixed abutment located on the upper, the device being positioned in the rear portion of the boot. The retaining device comprises a support mechanism that can be adjusted between two different positions with respect to the fixed abutment, one of the positions bringing the support mechanism to cooperate with the abutment, and the other position retracting it from the abutment.
With these arrangements, it is easy to adapt the boot for the alternating step or the skating step technique, because it suffices to displace the support mechanism with respect to the abutment, without any other maneuver to modify/adjust the amplitude of the possible rearward movement of the collar with respect to its initial angular position. Moreover, due to the fact that the support mechanism and the abutment are arranged in the rear portion of the boot, therefore at a distance from the journals of the collar, it is not necessary to use materials having high mechanical properties to obtain the various constituent parts of the adjusting device. Indeed, in view of the distance of the adjusting device with respect to the journals of the collar, the latter has a lesser lever effect than in the case of the known boots which comprise an adjusting device located in the area of the journals, as disclosed previously with reference to the document WO 91/07889.
According to a first embodiment of the invention, the cross-country ski boot comprises an elastic shock absorbing element inserted between the collar and the upper in the rear portion of the boot, and it is on this elastic element that the adjustable support mechanism of the retaining device is fixed. This elastic element can be independent of the collar, or affixed thereto, as taught in the document EP 0 596 281.
In a preferred construction, the elastic shock absorbing element is constituted by a flexible blade that extends over and opposite the fixed abutment by surrounding the rear portion of the upper, and whose ends are affixed to the collar in the area of the journals thereof on the upper; the adjustable support mechanism is, in this case, mounted on the flexible blade so as to be approximately centered with respect to the journals of the collar.
According to another embodiment, the cross-country boot comprises a collar with no shock absorbing means between it and the upper, the adjustable support mechanism of the retaining device then being directly fixed on the rear portion of the collar.
Regardless of the structure of the collar of the boot, i.e., with or without an elastic shock absorbing element, the adjustable support mechanism can be obtained in various ways, and its functioning can be carried out by pivoting, sliding, tilting, etc.
According to one example, the adjustable support mechanism is constituted by a pivoting piece that can be tilted between two angular positions of approximately 180xc2x0. This piece is made with an off-centered portion having a shaped end that is adapted to cooperate with the fixed abutment located on the upper in an angular position, and to retract from this fixed abutment in the other angular position, thus releasing the collar in rearward pivoting.
According to another example, the adjustable support mechanism is constituted by a movable lengthening piece that is guided in the rear portion of the collar, this lengthening piece being engaged above the fixed abutment of the upper for the adjusting position corresponding to the blocking of the collar in rearward pivoting, and being disengaged from the fixed abutment for the other adjusting position that corresponds to the rearward release of the collar. The movable lengthening piece can advantageously constitute the extension of the free end of a flexible tongue that is rotatably fixed on the rear portion of the collar, and its guiding can be carried out through an opening located in correspondence with the fixed abutment. The disengagement of the lengthening piece with respect to the latter then occurs by retraction of the flexible tongue, followed by a lateral rotation with respect to the guiding opening.
The movable lengthening piece can also be slidably mounted in a slider that confines it in the rear portion of the collar which carries it. In this case, a maneuvering member that can be accessed easily from outside the collar is provided to be capable of displacing it between two extreme adjusting positions, in one of which it is engaged above the fixed abutment and in the other of which it is disengaged therefrom.
In the example of construction of the collar with an elastic shock absorbing element between it and the upper, the adjustable support mechanism can be constituted by a removable piece that is fixed by elastic pinching on this shock absorbing element; in order to present two possible adjusting positions, this removable piece can be rotated at 180xc2x0 and is obtained approximately in the form of a U, one vertical arm of which is markedly thicker than the other. In this way, the thickest vertical arm cooperates with the fixed abutment located on the upper in an adjusting position of the support means and retracts from this abutment by a 180xc2x0 rotation of the latter by placing the thinnest vertical arm of the U opposite the abutment for the other adjusting position. In fact, one plays with the difference in the thickness of the vertical arms of the U to cause the support mechanism to cooperate or not cooperate with the fixed abutment.
According to an alternative embodiment of the invention, the adjustable support mechanism is constituted by an elastic shock absorbing element interacting between the collar and the abutment of the upper, on the one hand, and by a lever-cable tensioning system capable of retracting the elastic element from the fixed abutment by separating it therefrom by a certain distance so as to provide the collar with a possibility of reward tilting of a certain amplitude, and whose limit is determined by the recovery of the support of the shock absorbing element on the abutment.
In this alternative embodiment, the elastic shock absorbing element can consist of an elastic blade which, fixed to the collar in the area of its journals on the upper, surrounds the rear portion of the latter.